Definition

Anti-dengue antibodies are immune system proteins produced in response to dengue virus infection, which causes dengue fever and dengue hemorrhagic fever. When the immune system encounters the dengue virus, it responds by creating antibodies to combat the infection.

These antibodies exist in two main forms, IgM and IgG. They become detectable in the bloodstream within 3-7 days after symptoms of dengue fever or dengue hemorrhagic fever appear. IgM antibodies are generated during an initial infection, reaching peak levels around 10-14 days, after which they gradually decline. As IgM antibodies decrease, IgG antibodies increase and can persist for several months. In cases of re-infection, both IgM and IgG antibody levels can rise simultaneously. These antibodies are detected through an anti-dengue serology test, a key examination in diagnosing dengue infections, although other tests are often necessary for a precise diagnosis.

Dengue fever is prevalent in tropical regions, including Indonesia, where it poses a significant public health challenge, contributing to rising rates of morbidity and mortality. Timely diagnosis of dengue infections is critical in determining whether cases can be managed at home or require hospitalization.

Indications

Anti-dengue serology tests are used for various purposes, such as:

• Following travel to dengue-endemic areas with high case rates
• Experiencing dengue fever symptoms, such as a sudden high fever, severe headache, pain behind the eyes, joint, bone, and muscle pain, nosebleeds or bleeding gums, bruised skin, and low white blood cell (leukocyte) count
• Evaluating the severity of dengue virus infections to inform the prognosis and necessary level of care

Contraindications

There are no specific medical conditions that preclude this examination. The anti-dengue serology test is safe and straightforward.

Preparation Before the Test

No special preparation is required for the anti-dengue serology test. However, inform your doctor of any initial symptoms and when they began, as the timing of symptoms can influence when the test should be administered. Additionally, notify your doctor if you have had a previous dengue infection, as this information can help in interpreting the test results in the context of your current condition and medical history.

Test Procedure

The anti-dengue test involves drawing a blood sample from a vein. The procedure includes the following steps:

1. The healthcare professional selects the area for blood collection, typically in the crease of the arm.
2. A tourniquet is applied to the upper arm, and the patient is instructed to make a fist.
3. The site on the arm crease is cleansed with an antiseptic, such as an alcohol swab.
4. Once the skin dries, the syringe needle is inserted at the chosen site.
5. Blood is drawn into a syringe tube, typically collecting between 0.3 mL and 0.5 mL.
6. The tourniquet is released, and the needle is removed from the site.
7. Pressure is applied to the site with an alcohol swab to stop any bleeding.
8. The collected blood is then sent to the laboratory for analysis.

Normal and Abnormal Values

A normal result for the anti-dengue serology test shows negative IgM and IgG antibodies, indicating no detectable antibodies against the dengue virus in the blood. However, it is important to note that IgM and IgG antibodies may not be present in the early stages of infection.

Abnormal results are interpreted as follows (see Table 1):

Table 1. Abnormal Values of Anti-Dengue Serology Test

Results and Recommendations (Further Testing)

If both IgM and IgG antibody results are negative, this could indicate several possibilities:

1. No dengue infection: You are in good health with no active infection.
2. Early-stage infection: Dengue virus infection is possible, but antibodies may not be detectable yet if the test was conducted too soon.
3. Other viral infection: Similar symptoms might be due to another virus in the same family as the dengue virus. In this case, the doctor may recommend a repeat test in a few days or additional testing.

If the IgM result is positive and IgG is negative, this indicates an acute phase of dengue infection. When both IgM and IgG antibodies are positive, you are experiencing an active dengue infection. The doctor may then evaluate the severity of symptoms and consider if treatment for dengue hemorrhagic fever or dengue shock syndrome is needed.

If IgG levels show a four-fold increase from a previous test while IgM remains low or negative, this suggests a recent dengue infection, which may have been mild or severe, or possibly asymptomatic. If IgM remains low or negative and IgG is positive, this indicates a past infection and recovery.

Consult the Right Doctor

For any abnormal anti-dengue test results, it is important to consult a physician promptly. These results help determine the stage of infection, the potential severity of illness, and whether you may be in the recovery phase.

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